C# standalone: accept path to .dotnet folder

Author: mbg

csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/DependencyManager.cs

@@ -48,7 +48,7 @@ public DependencyManager(string srcDir, IDependencyOptions options, ILogger logg
 
             try
             {
-                this.dotnet = new DotNet(progressMonitor);
+                this.dotnet = new DotNet(options, progressMonitor);
             }
             catch
             {

csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/DependencyOptions.cs

@@ -56,6 +56,11 @@ public interface IDependencyOptions
         /// The number of threads to use.
         /// </summary>
         int Threads { get; }
+
+        /// <summary>
+        /// The path to the local ".dotnet" directory, if any.
+        /// </summary>
+        string? DotNetPath { get; }
     }
 
     public class DependencyOptions : IDependencyOptions
@@ -80,5 +85,7 @@ public bool ExcludesFile(string path) =>
             Excludes.Any(path.Contains);
 
         public int Threads { get; set; } = EnvironmentVariables.GetDefaultNumberOfThreads();
+
+        public string? DotNetPath { get; set; } = null;
     }
 }

csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/DotNet.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
+using System.IO;
 using Semmle.Util;
 
 namespace Semmle.Extraction.CSharp.DependencyFetching
@@ -10,12 +11,13 @@ namespace Semmle.Extraction.CSharp.DependencyFetching
     /// </summary>
     internal class DotNet : IDotNet
     {
-        private const string dotnet = "dotnet";
         private readonly ProgressMonitor progressMonitor;
+        private readonly string dotnet;
 
-        public DotNet(ProgressMonitor progressMonitor)
+        public DotNet(IDependencyOptions options, ProgressMonitor progressMonitor)
         {
             this.progressMonitor = progressMonitor;
+            this.dotnet = Path.Combine(options.DotNetPath ?? string.Empty, "dotnet");
             Info();
         }
 
@@ -29,7 +31,7 @@ private void Info()
             }
         }
 
-        private static ProcessStartInfo MakeDotnetStartInfo(string args, bool redirectStandardOutput) =>
+        private ProcessStartInfo MakeDotnetStartInfo(string args, bool redirectStandardOutput) =>
             new ProcessStartInfo(dotnet, args)
             {
                 UseShellExecute = false,
@@ -39,7 +41,7 @@ private static ProcessStartInfo MakeDotnetStartInfo(string args, bool redirectSt
         private bool RunCommand(string args)
         {
             progressMonitor.RunningProcess($"{dotnet} {args}");
-            using var proc = Process.Start(MakeDotnetStartInfo(args, redirectStandardOutput: false));
+            using var proc = Process.Start(this.MakeDotnetStartInfo(args, redirectStandardOutput: false));
             proc?.WaitForExit();
             var exitCode = proc?.ExitCode ?? -1;
             if (exitCode != 0)
@@ -77,7 +79,7 @@ public bool AddPackage(string folder, string package)
         private IList<string> GetListed(string args, string artifact)
         {
             progressMonitor.RunningProcess($"{dotnet} {args}");
-            var pi = MakeDotnetStartInfo(args, redirectStandardOutput: true);
+            var pi = this.MakeDotnetStartInfo(args, redirectStandardOutput: true);
             var exitCode = pi.ReadOutput(out var artifacts);
             if (exitCode != 0)
             {

csharp/extractor/Semmle.Extraction.CSharp.Standalone/Options.cs

@@ -53,6 +53,9 @@ public override bool HandleOption(string key, string value)
                 case "references":
                     dependencies.DllDirs.Add(value);
                     return true;
+                case "dotnet":
+                    dependencies.DotNetPath = value;
+                    return true;
                 default:
                     return base.HandleOption(key, value);
             }